In the manufacture of all kinds vehicle tyres a tyre blank or “green tyre” comprising several layers of unvulcanized rubber compounds is placed in a metal mould that produces the outer contour i.e. the profile, the sidewall geometry and the tread pattern of the tyre. In order to press the unvulcanized tyre blank into the metal mould contour a bladder is placed inside the green tyre and pressurised with hot steam. By means of the pressurised hot steam the bladder presses the green tyre into the cavity of the mould and heats the green tyre and thereby causes it to vulcanize. The bladder usually consists of rubber. Depending on tyre size and tyre type this process may take about 20-30 minutes.
In order to prevent the green tyre to adhere to the bladder during the vulcanization process a release agent is applied to the surface of the bladder that comes into contact with the green tyre. If no or insufficient release agent is applied to the bladder it may be difficult or impossible to separate the bladder from the vulcanized tyre. A bladder may be used for producing about 400-600 tyres, after which it due to strength and aging reasons, is replaced and discarded.
Release agents consisting based on silicone or talc are frequently used. In practice release agent will have to be applied again after a few, say 4-6, vulcanizations, because some of the release agent on the bladder is transferred to the inside (inner liner) of the resulting tyre.
Release agent left on the inside of a tyre may cause problems, in particular if e.g. a substance or part is later to be applied to the inner liner.
Examples of such substances are sealing substances for repair and sealing of punctures. This only works if there is no release agent on the inner liner.
Another example are measuring equipment, e.g. for temperature measuring of the tyre.
Therefore, the surface of the inner liner is cleaned using expensive and high energy consuming processes and polluting cleaning agents. But even washing works only with certain release agents and then only unsatisfactory.
Another example is that some automobile manufacturers adhere strips of acoustic foam on the inner liner in order to reduce tyre noise. This is currently only possible if the area to which the foam will be glued is mechanically roughened which may damage the inner liner.
The applicant has developed methods and substances, e.g. jelly or thixotropic substances, for being applied to the inner liner of a tyre for the purpose of balancing the tyre and/or the wheel on which the tyre is mounted. In order to confine such substances ribs are applied to the inner liner and it is necessary to clean the inner liner and remove any release agent before applying the ribs.
Various measures have been tested and applied such as                Cleaning with solvents        Cleaning with high pressure cleaner        Application of a primer        Mechanical roughening of the inner liner.        
Plasma treatment of thermoplastic materials and elastomers are known. However, for the purpose of modifying the surfaces such that other materials such as paint and other surface treatment will adhere very well afterwards. A typical example is the automotive industry where e.g. body parts such as bumpers are treated with low-pressure plasma to obtain good adherence of paint to the body part. These bumpers are typically made of PP or EPDM, and no other material will adhere well to these materials, and bumpers of these materials can not normally be durably painted. Through low pressure plasma treatment their surfaces are modified so that paint adheres well. Such modifications are normally performed in oxygen plasma.
U.S. Pat. No. 6,488,992 discloses that elastomeric seals, including O-rings, may have chemically resistant thin films applied by the technique of plasma polymerization to the surface of the elastomer, enhancing wear resistance and environmental resistance without changing the physical properties of the elastomer. The films may be a silane polymer applied by plasma deposition in a radio frequency/microwave dual power source reactor.
U.S. Pat. No. 5,198,033 discloses a plasma treatment apparatus for treating strip-stock material, such as tubing, wire, webs, and the like, by moving the strip-stock through a plasma treatment region of the apparatus provides improved consistency of surface treatment if the tension on the material is maintained within a predetermined range.
U.S. patent application 2009/289396 discloses a method for recycling polymeric materials, particularly cured rubber such as may be derived from tyres and the like, including obtaining solid polymer material in particulate form derived from a previous artifact or product. The polymer particles are exposed to a fluid treatment medium which chemically modifies the particle surfaces to provide chemically activated particle surfaces, while maintaining polymer properties in the particle interiors. The surface activated polymer particles are combined with a flowable binder or matrix material. The binder or matrix material is then cured, dried or set in intimate contact with the surface-activated polymer particles to form a body of material incorporating the recycled polymer particles with the surfaces bonded to the cured, dried or set binder or matrix material. In this way, large proportions of particulate material can be recycled into new products which exhibit good performance, e.g. elastomeric performance.
U.S. Pat. No. 4,214,014 discloses surface treatment for hard or dehydrated hydrophilic contact lenses, to reduce the deposit of impurities thereon, comprising subjecting the lens, after shaping and polishing, to a gas discharge, e.g. in an oxygen atmosphere.
WO 00/01528 A1 provides methods for chemically modifying particular surfaces using plasma surface modification. A method for preparing footwear having at least two components involves chemically modifying the surface of a component using plasma surface modification. The modified component surface is then adhered to a surface of another component. Functionalities that are added to the component surface by this technique include chlorine, oxygen and amine functionalities. The adhesion of a substrate is enhanced by chemically modifying a surface of the substrate using plasma surface modification to include chlorine and oxygen-containing functionalities, chlorine and amine functionalities, or amine and oxygen functionalities.